No one really expects drug dealers to buy a Minnesota Department of Revenue tax stamp to stick on their illegal stash.

But there it is in Minnesota law: A felony waiting to happen if authorities catch you with more than 42.5 grams of marijuana or seven or more grams of a controlled substance such as meth, without Revenue's small green sticker.

A mostly abandoned relic of the War on Drugs, the drug tax stamp would be just a curiosity if it weren't snaring narcotics offenders in one northwest Minnesota county. An enterprising prosecutor in Polk County, which covers East Grand Forks, has obtained 88 percent of the state's drug tax stamp convictions in the past decade. The latest charge came Aug. 29, when Crookston resident Jose Angel Fuentes, 32, was charged with "failure to affix tax stamps" after a drug raid uncovered $10,000 worth of methamphetamine in a wall.

Jason Horton, a 31-year-old Fertile, Minn., man busted for selling marijuana, pleaded guilty to the same charge last year. In an interview, Horton said he knew about the drug tax stamp because he was picked up for marijuana when he was 18. That time, authorities dropped the stamp charge, he said in an interview. This time, they didn't.

"My lawyer says it's one of those stupid laws out there," Horton said.

Horton said he didn't buy the drug stickers because he figured he'd be arrested if he did.

The Revenue Department says that's not the case. The tax stamp sales are anonymous, it says, and the confidential information can't be used in a criminal court proceeding except for one about the tax.

Fuentes and Horton are among the more than 1,100 Minnesotans charged, some repeatedly, under the statute over the years, according to a Star Tribune analysis of criminal records in the Minnesota Court Information System. Since most drug crimes are settled in plea bargains, and not before a jury, the stamp charges are often negotiated away and dismissed. There have been 223 convictions, records show.

Just bigger than a postage stamp, the stickers can be bought in person or by mail from the Revenue Department. Name and address are optional, the one-page form states. The tax is $3.50 per gram of marijuana, $200 per gram of controlled substance or $400 per 10 unit dose.

About 20 states have some version of the law. Enacted in 1986 when Reagan was president and the War on Drugs was in full swing, Minnesota's tax was originally a way to give law enforcement some flexibility to seize controlled substances at a time when forfeiture laws were much stricter, said Andrew Biggerstaff, a legislative analyst with the House Research Department. It survived a constitutional challenge in 1988. The easy-to-prove tax stamp violation was a way to get convictions and trigger other forfeiture laws, he said. As forfeiture laws loosened, the tax stamp law ultimately faded into "questionable utility."

It was most heavily used in the 1980s and early 1990s. Ramsey County hardly ever used it. Hennepin County has largely ditched it.

"I think we found it was not necessary and it caused more problems that it solved and we just discontinued doing it," said Hennepin County Attorney Mike Freeman. "We have a fairly meticulous bench and they don't like extra charges, so we don't give them."

Not so in Polk County.

That's largely thanks to Scott Buhler. An assistant Polk County attorney, Buhler has consistently applied the stamp charge wherever he can, he said in an interview.

"I've been told for years that I'm the guy up there that looks crazy because I charge the tax stamp," Buhler said. "All I've done is be consistent."

Buhler, whose career included a stint as an FBI special agent in Buffalo, N.Y., said the tax stamp charge has value as a bargaining chip.

"I simply charge it a lot because it leaves all options available regarding plea bargaining and sentencing," he said.

Hardball approach

Penalties for the felony tax violation typically aren't imposed consecutive to other drug charges, he said. Fines typically range from $50 to $500.

The hardball approach aggravates Joel Arnason, the assistant public defender on the receiving end of many of Buhler's cases. Arnason calls the failure to affix a "throwaway" charge.

"I just kind of roll my eyes and go, 'C'mon,' " Arnason said.

Horton, from Fertile, said his sentences ran concurrently and he served 8 months behind bars. He's kicked his habit, he said.

"I'm trying to get back to work," Horton said. "I've got two kids."

According to Revenue, it has sold about 2,079 drug tax stamps through 2013 yielding a total tax of $11,271.

A woman at the front desk said there seem to be a lot of stamp collectors, and the simply curious. "Some kids come in and think it's funny," said office specialist Marie Dodge.

Stephen Conlin, who runs a head shop called The Buzz in St. Charles, Minn., said he has bought about 1,350 tax stamps for marijuana over the years. An outspoken advocate for legalizing marijuana, Conlin claims that because the state statutes say marijuana is not a controlled substance, that it is legal.

"I'm the only person who has purchased the marijuana stamps with the intention of selling lawfully," Conlin said.

Conlin doesn't have his stamps at the moment. Law enforcement took them when they raided his shop in 2012, he said, and they are still in evidence.

A jury ultimately convicted Conlin of intent to sell marijuana and obstructing the legal process with force, complicating his unsuccessful run for mayor of St. Charles at the time. Conlin has appealed, arguing the raid was politically motivated. In his appeal, he argued that the 1986 drug tax stamp law helped raise the possibility of a lawful marijuana market.

The tax stamp law does not apply to medical marijuana, which is now legal.

Data editor Glenn Howatt contributed to this report.

Jennifer Bjorhus • 612-673-4683